import unittest, pprint
from pyyacc import Grammar, Item, ParserGenerationException, ParserException, EPS, EOF
from ppci import Token

def genTokens(lst):
    for t in lst:
        yield Token(t, t)

class testLR(unittest.TestCase):
    """ Test basic LR(1) parser generator constructs """
    def testSimpleGrammar(self):
        # 1. define a simple grammar:
        g = Grammar(['identifier', '(', ')', '+', '*'])
        g.add_production('input', ['expression'])
        g.add_production('expression', ['term'])
        g.add_production('expression', ['expression', '+', 'term'])
        g.add_production('term', ['factor'])
        g.add_production('term', ['term', '*', 'factor'])
        g.add_production('factor', ['(', 'expression', ')'])
        g.add_production('factor', ['identifier'])
        g.start_symbol = 'input'
        # 2. define input:
        tokens = genTokens(['identifier', '+', 'identifier', '+', 'identifier'])
        # 3. build parser:
        p = g.genParser()
        # 4. feed input:
        p.parse(tokens)
    def testReduceReduceConflict(self):
        """ Check if a reduce-reduce conflict is detected """
        # Define a grammar with an obvious reduce-reduce conflict:
        g = Grammar(['id'])
        g.add_production('goal', ['a'])
        g.add_production('a', ['b'])
        g.add_production('a', ['c'])
        g.add_production('b', ['id'])
        g.add_production('c', ['id'])
        g.start_symbol = 'goal'
        with self.assertRaises(ParserGenerationException):
            p = g.genParser()
    def testShiftReduceConflict(self):
        """ Must be handled automatically by doing shift """
        g = Grammar([EOF, 'if', 'then', 'else', 'ass'])
        # Ambiguous grammar:
        g.add_production('if_stmt', ['if', 'then', 'stmt'])
        g.add_production('if_stmt', ['if', 'then', 'stmt', 'else', 'stmt'])
        g.add_production('stmt', ['if_stmt'])
        g.add_production('stmt', ['ass'])
        g.start_symbol = 'stmt'
        p = g.genParser()
        # Ambiguous program:
        tokens = genTokens(['if', 'then','if', 'then', 'ass', 'else', 'ass' ])
        p.parse(tokens)

    def testUndefinedTerminal(self):
        """ Test correct behavior when a terminal is undefined """
        g = Grammar(['b'])
        g.add_production('goal', ['a'])
        g.add_production('a', ['b'])
        g.add_production('a', ['c'])
        g.start_symbol = 'goal'
        with self.assertRaises(ParserGenerationException):
            g.genParser()
    def testRedefineTerminal(self):
        """ Test correct behavior when a terminal is redefined """
        g = Grammar([EOF, 'b', 'c'])
        g.add_production('goal', ['a'])
        with self.assertRaises(ParserGenerationException):
            g.add_production('b', ['c']) # Not allowed
        g.add_production('a', ['c'])
        g.start_symbol = 'goal'
        g.genParser()
    def testEmpty(self):
        """ Test empty token stream """
        g = Grammar([','])
        g.add_production('input', [','])
        g.start_symbol = 'input'
        p = g.genParser()
        tokens = genTokens([])
        with self.assertRaises(ParserException):
            p.parse(tokens)
        
    def testEps(self):
        """ Test epsilon terminal """
        g = Grammar(['a', 'b'])
        g.add_production('input', ['optional_a', 'b'])
        g.add_production('optional_a', ['a'])
        g.add_production('optional_a', [])
        g.start_symbol = 'input'
        p = g.genParser()
        tokens = genTokens(['b'])
        p.parse(tokens)

    def testEps2(self):
        g = Grammar(['id', ':'])
        g.add_production('input', ['opt_lab', 'ins', 'op1'])
        g.add_production('input', ['ins', 'op1'])
        g.add_production('opt_lab', ['id', ':'])
        g.add_production('ins', ['id'])
        g.add_production('op1', ['id'])
        g.start_symbol = 'input'
        p = g.genParser()
        tokens = genTokens(['id', ':', 'id', 'id'])   # i.e. "lab_0: inc rax" 
        p.parse(tokens)
        tokens = genTokens(['id', 'id'])   # i.e. "inc rax"
        p.parse(tokens)


class testExpressionGrammar(unittest.TestCase):
    def setUp(self):
        g = Grammar(['EOF', 'identifier', '(', ')', '+', '*', 'num'])
        g.add_production('input', ['expression'])
        g.add_production('expression', ['term'])
        g.add_production('expression', ['expression', '+', 'term'])
        g.add_production('term', ['factor'])
        g.add_production('term', ['term', '*', 'factor'])
        g.add_production('factor', ['(', 'expression', ')'])
        g.add_production('factor', ['identifier'])
        g.add_production('factor', ['num'])
        g.start_symbol = 'input'
        self.g = g

    def testFirstSimpleGrammar(self):
        # 1. define a simple grammar:
        first = self.g.calcFirstSets()
        self.assertEqual(first['input'], {'identifier', '(', 'num'})
        self.assertEqual(first['term'], {'identifier', '(', 'num'})

    def testCanonical(self):
        s0 = self.g.initialItemSet()
        s, gt = self.g.genCanonicalSet(s0)
        # Must result in 12 sets:
        self.assertEqual(len(s), 24)

class testPG(unittest.TestCase):
    """ Tests several parts of the parser generator """
    def setUp(self):
        g = Grammar(['(', ')'])
        g.add_production('goal', ['list'])
        g.add_production('list', ['list', 'pair'])
        g.add_production('list', ['pair'])
        g.add_production('pair', ['(', 'pair', ')'])
        g.add_production('pair', ['(', ')'])
        g.start_symbol = 'goal'
        self.g = g

    def testFirstSet(self):
        for a in ['(', ')', EOF, 'EPS']:
            self.assertEqual(self.g.first[a], {a})
        for nt in ['list', 'pair', 'goal']:
            self.assertEqual(self.g.first[nt], {'('})

    def testInitItemSet(self):
        p0, p1, p2, p3, p4 = self.g.productions
        s0 = self.g.initialItemSet()
        self.assertEqual(len(s0), 9)    # 9 with the goal rule included!
        self.assertIn(Item(p0, 0, EOF), s0)
        self.assertIn(Item(p1, 0, EOF), s0)
        self.assertIn(Item(p1, 0, '('), s0)
        self.assertIn(Item(p2, 0, EOF), s0)
        self.assertIn(Item(p2, 0, '('), s0)
        self.assertIn(Item(p3, 0, EOF), s0)
        self.assertIn(Item(p3, 0, '('), s0)
        self.assertIn(Item(p4, 0, EOF), s0)
        self.assertIn(Item(p4, 0, '('), s0)

    def testCanonical(self):
        s0 = self.g.initialItemSet()
        s, gt = self.g.genCanonicalSet(s0)
        # Must result in 12 sets:
        self.assertEqual(len(s), 12)

    def testClosure(self):
        p0, p1, p2, p3, p4 = self.g.productions
        s0 = set()
        s0.add(Item(p0, 0, EOF))
        self.assertEqual(len(s0), 1)    # 1 rule
        self.assertIn(Item(p0, 0, EOF), s0)

        # Invoke closure on set:
        s0 = self.g.closure(s0)
        self.assertIn(Item(p0, 0, EOF), s0)
        self.assertIn(Item(p1, 0, EOF), s0)
        self.assertIn(Item(p1, 0, '('), s0)
        self.assertIn(Item(p2, 0, EOF), s0)
        self.assertIn(Item(p2, 0, '('), s0)
        self.assertIn(Item(p3, 0, EOF), s0)
        self.assertIn(Item(p3, 0, '('), s0)
        self.assertIn(Item(p4, 0, EOF), s0)
        self.assertIn(Item(p4, 0, '('), s0)

    def testParser(self):
        tokens = ['(', '(', ')', ')', '(', ')']
        # 3. build parser:
        p = self.g.genParser()
        self.assertEqual(len(p.goto_table), 5)
        self.assertEqual(len(p.action_table), 19)

        # 4. feed input:
        p.parse(genTokens(tokens))

if __name__ == '__main__':
    unittest.main()